商用高分子纖維與共軛巨分子的繞射微結構分析

Abstract

本研究致力於以X光繞射分析技術，鑑定樣品的微結構，以建立一個能夠提供工業界及學術界使用的結構鑑定平台。在本論文的第一個部分，我們與遠東新世紀股份有限公司研發中心合作，以PET工業纖維為研究對象，探討PET纖維之微結構與其機械性質的關係。我們發現PET纖維若能在紡絲過程中形成較厚的層狀結晶且具有較高的非晶區取向性，則該纖維的機械強度會上升。且紡絲後的熱處理會使非晶區內高分子鏈的可動性上升，使其取向性下降，而造成延伸率增加且收縮率降低的結果，然而二者相伴發生，故PET纖維仍能維持良好的機械性質。 接著，以X光繞射分析技術探討共軛POSS分子的結晶堆疊原則，我們發現其固態結構會隨支鏈改變而有所變化，當在共軛支鏈上修飾長碳鏈時，長碳鏈會發生分子間交纏的現象，形成二對稱的正交晶系結構。而當支鏈上不具有長碳鏈時，POSS分子的自組裝改由π-π堆疊作用力主導，形成具有C3轉軸的固態結晶結構。

In this research, we try to build up a platform to identify microstructure for the academic world and the industry. In order to achieve this goal, we focus on developing an X-ray diffraction analysis method for determination the microstructure of material. In the first part of the thesis, we corporate with R&D center of Far Eastern New Century Corporation, and study the microstructure of the industry PET fiber. By using the X-ray diffraction, we can determine the relationship between the microstructure in the PET fiber and its mechanical properties. As the result, we find that if the spinning and drawing process can induce the thicker lamellar crystal and the more oriented amorphous domain, then you will get the better mechanical strength. We also figure out that the thermal treatment will increase the polymer chain mobility of the amorphous domain, so the amorphous orientation will decrease after thermal anneal. The polymer chain in the amorphous domain are less extended, so the elongation percentage increase and the hot air shrinkage decrease after temperature treament. Over all speaking, the two factor will cancel out each other. As the result, these PET fibers still can provide us really nice mechanical properties. Next, we use the X-ray diffraction and the electron diffraction analysis method to study the packing principle of the POSS molecules. We can see that the crystal structure of the POSS molecules will change with different side chains. The conjugated POSS molecules with long alkyl chain substituents were seen to have entanglement, and form the orthorhombic crystal structure. However, as for the counterpart without long alkyl chain, the driving force of the crystal packing will be dominated by the π-π stacking, such that these kind of conjugated POSS molecules would form the C3 symmetry structure.